The technology disclosed herein generally relates to flight management systems for airplanes and, more particularly, relates to techniques for computing predicted flight profile and associated trip prediction parameters in a flight management system.
A flight management system installed in the flight deck of a modern airplane performs various flight critical functions such as navigation, guidance, flight planning, datalink and performance. For the performance function, the flight management system has various internal algorithms (hereinafter “performance algorithms”) that utilize aerodynamic and propulsion performance data (hereinafter “baseline performance data”) stored in a performance database to compute the predicted flight profile and the associated trip prediction parameters such as speed, altitude, estimated time of arrival (ETA) and the predicted fuel consumption. However, the airplane characteristics may vary over time due to small but incremental changes to the airplane aerodynamic and propulsion performance. For example, due to changes to an airframe, such as repairs, antennas, configuration changes, etc., and engine deterioration, the airplane fuel flow and drag characteristics change over time. As a result, the performance algorithms and the baseline performance data may deviate from the actual airplane performance over time as the airplane continues to operate in service. This creates a situation where airlines would like to update the performance database with up-to-date tables in a timely and efficient manner to reflect the true airplane performance.
Many airlines are looking to enhance fuel performance through extensive on-ground flight/fuel planning to reflect the true fuel flow and drag characteristics of individual airplanes. The performance database in the flight management system contains aerodynamics and propulsion data that is representative of a series of flight tests that usually occur in a controlled environment before the airplane is delivered to a customer airline. It is necessary to update the performance database with up-to-date tables in a timely and efficient manner to reflect the true airplane performance. Currently, it is not possible to update the performance database tables in the flight management system via datalink. In fact, the current FMS datalink cannot uplink or downlink any data in a tabular or polynomial (i.e., curve) format.
While the airplane is sitting on the ground, maintenance crew needs to send a performance database request downlink from the flight deck of the airplane to initiate the transfer of a new (i.e., updated) performance database into the flight management system. This usually increases time and labor costs for the airlines. The time window during which maintenance crew can enter the flight deck to load the new performance database into the flight management system is very limited.
It would be advantageous to provide a flight management system that is configured to incorporate performance tables that have been uploaded via the FMS datalink capability.